# Solar system encounters a gas dense cloud of interstellar gas and dust - what happens? **URL:** \ **Category:** Factual Questions\ **Created:** [April 22, 2020, 12:24pm UTC](https://boards.straightdope.com/t/solar-system-encounters-a-gas-dense-cloud-of-interstellar-gas-and-dust-what-happens/852337 "2020-04-22T12:24:36Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![kanicbird](https://avatars.discourse-cdn.com/v4/letter/k/5f8ce5/32.png) [@kanicbird](https://boards.straightdope.com/u/kanicbird)\ **Post date:** [April 22, 2020, 12:24pm UTC](https://boards.straightdope.com/t/solar-system-encounters-a-gas-dense-cloud-of-interstellar-gas-and-dust-what-happens/852337/1 "2020-04-22T12:24:36Z")
If the solar system ran into a gas cloud like the one that is thought to have started the solar system, what happens. Would the sun grow more then 2x it’s mass or the cloud be blown away by the solar wind and never enter the solar system? Would the planets and atmospheres enlarge, and rings form? How long would it take for the effects to happen if they do? ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [April 22, 2020, 10:59pm UTC](https://boards.straightdope.com/t/solar-system-encounters-a-gas-dense-cloud-of-interstellar-gas-and-dust-what-happens/852337/2 "2020-04-22T22:59:29Z")
Assuming the cloud hasn’t collapsed to the point of forming a star, the solar wind will just push the stuff out of the way. The heliopause will compress some, but that won’t affect what happens on the planets. ---
**Author:** ![md2000](https://avatars.discourse-cdn.com/v4/letter/m/73ab20/32.png) [@md2000](https://boards.straightdope.com/u/md2000)\ **Post date:** [April 23, 2020, 5:14am UTC](https://boards.straightdope.com/t/solar-system-encounters-a-gas-dense-cloud-of-interstellar-gas-and-dust-what-happens/852337/3 "2020-04-23T05:14:09Z")
Dense cloud of gas is a relative term in interstellar space. The atmosphere of the moon (basically none) is dense compared to that. We wouldn’t notice it. Solar wind (particles) and light pressure would sweep anything away before it got close. ---
**Author:** ![Der\_Trihs](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/der_trihs/32/233_2.png) [@Der\_Trihs](https://boards.straightdope.com/u/Der_Trihs)\ **Post date:** [April 23, 2020, 5:27am UTC](https://boards.straightdope.com/t/solar-system-encounters-a-gas-dense-cloud-of-interstellar-gas-and-dust-what-happens/852337/4 "2020-04-23T05:27:52Z")
It’s my [understanding](http://www-news.uchicago.edu/releases/96/960609.solar.sytem.crash.shtml) that it could greatly compress the “heliosphere”, potentially causing all sorts of effects. > [@](#): > > But if the solar system encountered the much denser cloud, Frisch estimates that the heliosphere could be compressed to within one or two astronomical units of the Sun, not much greater than the Earth’s distance from the Sun. “There would be dramatic effects on the inner solar system,” said Frisch. “It would immediately change the whole interaction between the solar wind and the interstellar medium.” Researchers have predicted increases in the cosmic-ray flux, changes in the Earth’s magnetosphere, the chemistry of the atmosphere and perhaps even the terrestrial climate. ---
**Author:** ![si\_blakely](https://avatars.discourse-cdn.com/v4/letter/s/d9b06d/32.png) [@si\_blakely](https://boards.straightdope.com/u/si_blakely)\ **Post date:** [April 23, 2020, 10:05pm UTC](https://boards.straightdope.com/t/solar-system-encounters-a-gas-dense-cloud-of-interstellar-gas-and-dust-what-happens/852337/5 "2020-04-23T22:05:12Z")
We try and communicate with it? [**The Black Cloud**](https://en.wikipedia.org/wiki/The_Black_Cloud) by _Fred Hoyle_ ---
**Author:** ![Exapno\_Mapcase](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/exapno_mapcase/32/1051_2.png) [@Exapno\_Mapcase](https://boards.straightdope.com/u/Exapno_Mapcase)\ **Post date:** [April 23, 2020, 10:17pm UTC](https://boards.straightdope.com/t/solar-system-encounters-a-gas-dense-cloud-of-interstellar-gas-and-dust-what-happens/852337/6 "2020-04-23T22:17:22Z")
> [@Der\_Trihs](#): > > It’s my [understanding](http://www-news.uchicago.edu/releases/96/960609.solar.sytem.crash.shtml) that it could greatly compress the “heliosphere”, potentially causing all sorts of effects. It’s vaguely possible that we’ve learned more about astronomy since 1996. ---
**Author:** ![RioRico](https://avatars.discourse-cdn.com/v4/letter/r/f04885/32.png) [@RioRico](https://boards.straightdope.com/u/RioRico)\ **Post date:** [April 23, 2020, 11:48pm UTC](https://boards.straightdope.com/t/solar-system-encounters-a-gas-dense-cloud-of-interstellar-gas-and-dust-what-happens/852337/7 "2020-04-23T23:48:21Z")
Has OP seen any heading this way? ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [April 24, 2020, 12:12am UTC](https://boards.straightdope.com/t/solar-system-encounters-a-gas-dense-cloud-of-interstellar-gas-and-dust-what-happens/852337/8 "2020-04-24T00:12:46Z")
I hope the OP hasn’t seen any in this neighborhood, since astronomers have not. The sun seems to be near the edge of a [Local Interstellar Cloud](https://en.wikipedia.org/wiki/Local_Interstellar_Cloud) and heading toward the [G-Cloud](https://en.wikipedia.org/wiki/G-Cloud), which Alpha Centauri and other stars currently reside in. Neither of these have anywhere near the density of a nebula that’s going to collapse to a protostar. In fact, they are within in a larger low-density cavity in the interstellar medium called the [Local Bubble](https://en.wikipedia.org/wiki/Local_Bubble).